Conversly, if they lovingly craft an RST that renders wonderfully in all derived formats, then corrections to the RST will automatically propagate.
Fundamentally, if RST (picked on only as the example at hand) renders wonderfully in all derived formats, it is because RST has restricted the set of operations it supports to that subset of all operations found in all target machines. Which is why restricted formats end up looking so bland. One can find blandified versions of PG works for free from many many secondary vendors including Amazon. It always saddens me to see these inferior versions being propagated vs. the richer and more accurate versions which were originally submitted by volunteers to PG. One reason that HTML is such a pain for small machines is that many HTML submitters *want* to use the richer set of features only suitable to larger machines.